json.wrf parameter ignored in JacksonJsonWriter

When requesting json output in 9.3 using json.wrf to trigger a JSONP request, the return is not wrapped in a function and is instead returned as a plain JSON object

 My test cases are:

wt=json&json.wrf=ng_jsonp_callback_0 on Solr 9.3.0

 { "responseHeader":{ "status":0, "QTime":9, "params":{

 wt=json&json.wrf=ng_jsonp_callback_0 on Solr 7.3.1

 ng_jsonp_callback_0({ "responseHeader":{ "status":400, "QTime":206, "params":{